The Status of VirgoJo van den Brand, Spokesperson of Virgo

Nikhef and VU University Amsterdam, jo@nikhef.nl

The 5th KAGRA International Workshop, Perugia, February 14, 2019

Virgo Collaboration is growing and new groups are being integrated into Virgo

Status of Virgo 3

Scientific highlights 7

Commissioning 19

Computing and Data Processing 31

Upgrade project AdV+ 35

Path towards Einstein Telescope 47

Summary and outlook 57

2

Contents

Virgo is a European collaboration with more than 300 members

Advanced Virgo (AdV): upgrade of the Virgo interferometric detector

Participation by scientists from France, Italy, Belgium, The Netherlands, Poland, Hungary, Spain, Germany

• 24 laboratories, about 280 authors

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Virgo Collaboration

− APC Paris

− ARTEMIS Nice

− EGO Cascina

− IFAE Barcelona

− INFN Firenze-Urbino

− INFN Genova

− INFN Napoli

− INFN Perugia

− INFN Pisa

− INFN Roma La

Sapienza

− INFN Roma Tor Vergata

− INFN Trento-Padova

− LAL Orsay – ESPCI

Paris

− LAPP Annecy

− LKB Paris

− LMA Lyon

− Nikhef Amsterdam

− POLGRAW(Poland)

− RADBOUD Uni.

Nijmegen

− RMKI Budapest

− UCLouvain

− ULiege

− Univ. of Barcelona

− Univ. of Valencia

− University of Jena

Advanced Virgo project has been

formally completed on July 31, 2017

Part of the international network of 2nd

generation detectors

Joined the O2 run on August 1, 2017

8 European countries

Most infrastructure installed for Advanced Virgo. It features many improvements with respect to Virgo

and Virgo+. However the absence of Signal Recycling has great impact

Instrumentation improvements for Observing run 2

• Larger beam: 2.5x larger at ITMs

• Heavier mirrors: 2x heavier

• Higher quality optics: residual roughness < 0.5 nm

• Improved coatings for lower losses:

absorption < 0.5 ppm, scattering < 10 ppm

• Reducing shot noise: arm finesse of cavities are

3 x larger than in Virgo+

• Thermal control of aberrations: compensate for cold

and hot defects on the core optics:

ring heaters

double axicon CO2 actuators

CO2 central heating

diagnostics: Hartmann sensors & phase cameras

• Stray light control: suspended optical benches in

vacuum, and new set of baffles and diaphragms to

catch diffuse light

• Improved vacuum: 10-9 mbar instead of 10-7 mbar

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Advanced Virgo

New groups strengthen Virgo in areas as Computing and Stray Light Mitigation

2018: IFAE and UBarcelona, ULiège and UCLouvain

UCL Louvain-la-Neuve

ULiège

UBarcelona

IFAE Barcelona

Groups from UTorino, UMaastricht,

USannio, USardinia joined Virgo indirectly

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LVC scientific output

Sources can be transient or of continuous nature, and can be modeled or unmodeled

LIGO-Virgo analyses for sources of gravitational waves

Asymmetric core collapse supernovae(and other poorly modeled events)

Rapidly rotating neutron stars(with lumps on them)

A stochastic, unresolvable background(from the Big Bang, or all of the above)

Burst Stochastic

Coalescence of Compact Sources Continuous Waves

Colliding binary systems(e.g. black holes, neutron stars)

Scientific achievements: properties of black holesExtract information on masses, spins, energy radiated, position, distance, inclination,

polarization. Population distribution may shed light on formation mechanisms

Abbott et al. ApJ 851 (2017) L35LVC reported on 10 BBH mergers (and 1 BNS)

Chirp mass is well inferred

Merger dynamics more sensitive to total mass

“GWTC-1: A Gravitational-Wave Transient Catalog of

Compact Binary Mergers Observed by LIGO and Virgo

during the First and Second Observing Runs”, The

LIGO Virgo Collaboration, arXiv:1811.12907

Properties of black holesExtract information on masses, spins, energy radiated, position, distance, inclination,

polarization. Population distribution may shed light on formation mechanisms

“GWTC-1: A Gravitational-Wave Transient Catalog of Compact Binary Mergers Observed by LIGO

and Virgo during the First and Second Observing Runs”, The LIGO Virgo Collaboration,

arXiv:1811.12907

Table of O1 and O2 triggers with source propertiesSee https://dcc.ligo.org/LIGO-G1801864

Table of O1 and O2 triggers with source propertiesSee https://dcc.ligo.org/LIGO-G1801864

Virgo data contributed to Parameter Estimation of 5 events

August 14, 2017 three detectors observed BBH. Initial black holes were 31 and 25 solar mass, while

the final black hole featured 53 solar masses. About 3 solar mass radiated as pure GWs

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First triple detection by Virgo and LIGO

Abbott et al.

PRL 119, 141101 (2017)

Polarization is a fundamental property of spacetime. It determined how spacetime can be deformed.

General metric theories allow six polarizations. General Relativity allows two (tensor) polarizations

GR only allows (T) polarizations

General metric theories also know

vector (V) and scalar (S) polarizations

Polarization of gravitational waves

According to Einstein’s General Relativity there exist only two polarizations. General metric theories

of gravity allow six polarizations. GW170814 confirms Einstein’s prediction

Angular dependence (antenna-pattern) differs for T, V, S

LIGO and Virgo have different antenna-patterns

This allows for a fundamental of the polarizations of spacetime

First test of polarizations of gravitational waves

According to Einstein’s General Relativity there exist only two polarizations. General metric theories

of gravity allow six polarizations. GW170814 confirms Einstein’s prediction

Angular dependence (antenna-pattern) differs for T, V, S

LIGO and Virgo have different antenna-patterns

This allows for a fundamental of the polarizations of spacetime

First test of polarizations of gravitational waves

Our analysis favors tensor polarizations in support of General

Relativity

Our data favor tensor structure over vector by about a (Bayes) factor 200

And tensor over scalar by about a factor 1000

This is a first test, and for BBH we do not know the source position very well

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Virgo allowed source location via triangulationGW170817 first arrived at Virgo, after 22 ms it arrived at LLO, and another 3 ms later LLH detected it

LIGO, Hanford, WA

LIGO, Livingston, LA

Virgo, Cascina, Italy

Distributed skymapsSee https://dcc.ligo.org/LIGO-G1801864

GW170817

GW170814

GW170818

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Scientific impact of gravitational wave scienceMulti-messenger astronomy started: a broad community is relying of detection of gravitational waves

Fundamental physics

Access to dynamic strong field regime, new tests of General Relativity

Black hole science: inspiral, merger, ringdown, quasi-normal modes, echo's, primordial, no-hair

Black hole mimickers, Lorentz-invariance, equivalence principle, polarization, parity violation, axions

Astrophysics

First observation for binary neutron star merger, relation to sGRB

Evidence for a kilonova, explanation for creation of elements heavier than iron

Astronomy

Start of gravitational wave astronomy, population studies, formation of progenitors, remnant studies

Cosmology

Binary neutron stars can be used as standard “sirens”

Dark Matter and Dark Energy, stochastic background

Nuclear physics

Tidal interactions between neutron stars get imprinted on gravitational waves

Access to equation of state, phase transitions

LVC will be back with improved instruments to start the next observation run (O3) early this year

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Commissioning

From the 2013 ‘‘Observing Scenario’’, arXiv:1304.0670. We projected at least 60 Mpc for O3.

Note that LIGO aims at > 120 Mpc

All four test masses are suspended with steel wires

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Projected sensitivity evolution for Virgo

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Virgo sensitivity: significant improvement wrt O2Comparison to the best sensitivity obtained in O2. Monolithic suspensions are now installed

Flat noise contribution in mid-frequency range, and significant 50 Hz noise

LIGO and Virgo scheduled ER13 and ER14 engineering runs to prepare for observation run O3

ITF input power 18 W

• ER13 (4 days) just completed

• ER14 (4 weeks) starts around March 1, 2019

• O3 begins in April 2019

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Engineering runs and next observation run

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Engineering run ER13

Virgo science mode

duty cycle 65%

Goals of ER13

• End-to-end test of the Open Public Alert (OPA) software

• Rapid Response Team (RRT) exercise

• Test of new Data Quality Reporting on online data

ER13 lasted from December 14 – 18, 2018

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Engineering run ER13

Dashed lines: best O2 performance

Comparison to the best sensitivity obtained in O2

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Engineering run ER13

Dashed lines: best O2 performance

Virgo aims at BNS range > 60 Mpc

• Commissioning in progress. Also at LIGO

• Rapid Response Team (RRT) exercise

• Test of new Data Quality Reporting on online data

• Follow-up meeting to discuss retracted OPA

Comparison to goals set for O3

V1 Goal

H1, L1 Goal

Comparison to L1 and H1

Virgo’s strain sensitivity

• Effect of no signal recycling is apparent. Also injected laser power 18 W, no squeezing, 3 km, …

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Virgo will implemented signal recycling after O3

Sensitivity (BNS range) has now reached 55 Mpc. Further improvements are explored: implement

squeezing, reduce 50 Hz noise, and/or reduce “flat” noise contribution

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Virgo’s best sensitivity so far

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SqueezingThe AEI squeezer installed in Virgo’s DET lab. Squeezer can deliver up to 14 dB of squeezed light

Squeezer connected with electronics, and operating: same squeezing level obtained as in Hannover

Set up external bench (telescopes,...), replaced in-vacuum Faraday isolator, alignment and

commissioning

Implementation of frequency independent squeezing is underway

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Squeezing

Main activities

Significant priority since October 2018

Completed hardware installation: injection 10 dB and expected losses = 40% (see VIR-0745A-18)

+10% (technical noise) = 50%

Set up and optimize control loops: coherent control and automatic alignment

Mitigation of back-scattered light

Preliminary results

Measured a peak SQZ injection of almost 2 dB

(3 dB is our O3 target)

BNS range improvement of 2-3 Mpc to 55 Mpc

Inferred losses 60-70%

Need to improve stability

Main objective

Identify technical noise contributions at mid frequency

Carry out a systematic study to identify technical performance. Identify tests, interpret test results,

generate ideas for new tests. Rapid turn around with help of PhD students, postdocs

Current candidate: working point of ITF

Full priority over all other ITF activities: CC sets priority

Meetings: dedicated discussions tagged on to weekly Commissioning and Detchar meetings

Wiki to list status and progress: https://wiki.virgo-gw.eu/Commissioning/FlatNoise

Parallel activities

Electronics to achieve improved 50 Hz robustness is under preparation

System to discharge mirrors is under investigation

Focus on stability

Reliability and risk reduction

Commissioning has the highest priority

Virgo Computing and Data Processing

Recent developments and boundary conditions

Computing situation for LVC is becoming a

bottleneck

• Virgo is making an effort to increase its contribution to

LVC computing resources for DA

• Recent focus on LV Continuous Wave analysis

• Note that all O2 data will become public in February

2019

Virgo Computing and offline Data processing

CNRS Lyon

Nikhef Amsterdam

CNAF Bologna

VSC agreed (August 29, 2018) to implement a new Virgo CDP subsystem (supersede VDAS). New

structure is also recommended by ECC

New organization

• Local computing and low latency computing

• Offline computing management

Management

• DPI: EGO-Virgo Data Processing Infrastructure coordinator

• CDP: Virgo Computing and Data Processing coordinator

Scope

• DPI and CDP will work closely with other coordinators (DAQ and DA)

• Report to EGO Director and Virgo Spokesperson

Virgo Computing and Data Processing

WBS and Projects with clear deliverables have been defined. Resources have been allocated

CW: Complete LV data analyses on Continuous Waves and secure LVC publications

GstLAL: Allow most important CBC pipelines to run on European grid-computing resources. Start

with GstLAL, but expand to other LV pipelines

LVC: I. Update VCDP Computing Model, Implementation Plan, and Management Plan (involve DA

and CDP coordinators), and II. Prepare a strategy in collaboration with LSC and Computing Centers

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Project deliverables

35

What’s next?

Towards a global network KAGRA expected to join LIGO and Virgo in Observation run 3

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Planned observing timelineOne-year O3 planned to start in April 2019 with about twice the sensitivity in O3 (thus about 23 in rate).

In O3 LIGO and Virgo will release Open Public Alerts

Observation run O3

Three detectors and perhaps 1 event per week

KAGRA expected to join at the end of O3

Contribute to sky localization and PEProspects for Observing and Localizing GW Transients with aLIGO, AdV and KAGRA 7

LIGO

Virgo

2015 2016 2017 2018 2019 2020 2021 2022 2023

KAGRA

60-80

Mpc

Early Mid Late Design

60-100

Mpc

O2 O3O1

O3

190

Mpc

125

Mpc

140

Mpc

O2

120-170

Mpc

25-30

Mpc

65-85

Mpc

65-115

Mpc

25-40

Mpc

40-140

Mpc

Fig. 2 Theplannedsensitivity evolutionandobservingrunsof theaLIGO, AdV andKAGRA detectors

over thecomingyears. Thecoloredbarsshowtheobservingruns, withtheexpectedsensitivitiesgivenby

thedatainFigure1for futureruns, andtheachievedsensitivitiesinO1andinO2. Thereissignificant

uncertainty inthestart andendtimesof plannedtheobservingruns, especially for thosefurther inthefuture,

andthesecouldmoveforwardor backwardsrelativetowhat isshownabove. Theplanissummarisedin

Section 2.2.

2015–2016 (O1) A four-monthrun(12September 2015–19January 2016) withthe

two-detector H1L1networkat early aLIGOsensitivity (60–80Mpc BNS range).

This is now complete.

2016–2017 (O2) A nine-month runwithH1L1, joined by V1for thefinal month.

O2 began on 30 November 2016, with AdV joining 1 August 2017 and ended on

25August 2017. TheexpectedaLIGOrangewas80–120Mpc, andtheachieved

rangewasintheregionof 60–100Mpc; theexpectedAdV rangewas20–65Mpc,

and the initial range was 25–30 Mpc

2018–2019 (O3) A year-longrunwithH1L1at 120–170Mpc andwithV1at 65–

85 Mpc beginning about ayear after the end of O2.

2020+ Three-detector network withH1L1at full sensitivity of 190Mpc andV1at

65–115 Mpc, later increasing to design sensitivity of 125 Mpc.

2024+ H1L1V1K1I1networkat full sensitivity (aLIGOat 190Mpc,AdV at 125Mpc

andKAGRA at 140Mpc). Includingmoredetectorsimprovessky localization[61,

62,63,64] aswell asthefraction of coincident observational time. 2024 isthe

earliest time we imagine LIGO-India could be operational.

This timeline issummarized in Figure2; wedo not include observing runs with

LIGO-Indiayet, asthesearestill tobedecided. Additionally, GEO600will continue

observing, withfrequent commissioningbreaks, duringthisperiod. Theobservational

implications of these scenarios are discussed in Section 4.

B. P. Abbott et al., Prospects for Observing and Localizing Gravitational-Wave Transients

with Advanced LIGO, Advanced Virgo and KAGRA, 2016, Living Rev. Relativity 19

~60% in 10 sq deg HIKLV 2024

HLV 2019~20% in 20 sq deg

AdV+ as the next incremental step forward in sensitivityAdV+ is the plan to maximize Virgo’s sensitivity within the constrains of the EGO site. It has the

potential to increase Virgo’s detection rate by up to an order of magnitude

AdV+ features

Maximize science

Secure Virgo’s scientific relevance

Safeguard investments by scientists and funding agencies

Implement new innovative technologies

De-risk technologies needed for third generation observatories

Attractive for groups wanting to enter the field

Upgrade activities

Tuned signal recycling and HPL: 120 Mpc

Frequency dependent squeezing: 150 Mpc

Newtonian noise cancellation: 160 Mpc

Larger mirrors (105 kg): 200-230 Mpc

Improved coatings: 260-300 Mpc

Phase IQuantum noise will be tackled after the O3 science run in Phase 1: installation in 2020

Power increase

All in-fiber 200 W laser system for 125 W after the IMC

Foreseen as part of AdV

Tuned signal recycling: 120 Mpc

Install SR mirror

Control additional DOF (auxiliary lasers?)

Frequency dependent squeezing: 150 Mpc

Squeezed light source and filter cavity

Newtonian noise cancellation: 160 Mpc

Seismic sensor networks

Phase IIReduce thermal noise: modify optical design of the Fabry-Perot arms to accommodate larger beams

and heavier test masses

Larger mirrors

Diameter: 550 mm, thickness: 200 mm, mass: 105 kg

Scenario 1: ETM-only → 200 Mpc

Scenario 2: full upgrade → 230 Mpc

Coating research

Factor three reduction in CTN

Scenario 1: ETM-only → 260 Mpc

Scenario 2: full upgrade → 300 Mpc

Grand Coater upgrade

Many activities

Vacuum, infrastructure

Payloads and superattenuators

Aberration control

The AdV – AEI Squeezing Working Group prepared a Conceptual Design (transverse activity)

Optical loss, injection losses, noise tolerances

Technical noise and phase noise

Filter cavity: cavity length and finesse

Stray light considerations

Infrastructure

Overall layout

Minitower and control microtower locations

Cavity mirrors locations

Suspensions

Optical benches and mirrors suspensions

Optics, optical layout, filter cavity mirrors

OPO location

Filter cavity control schemes

Suspended bench optical links

General layout

In-air squeezed light source operation

In-vacuum squeezed light source operation

Frequency dependent squeezing in the post-O4 era: EPR-entanglement

FDS Conceptual Design Report

PBS follows the hardware components (not a WBS)

Responsibilities for construction of items for AdV+ have been allocated

a) Optical design and preparations for FDS ongoing

b) Smart infrastructure (HVAC) for NNC: under discussion

FDS Project Breakdown Structure

Virgo squeezer from AEI Hannover

Improvements to the infrastructure are expected to have a large impact

Noise at Central Building is about an order of magnitude higher than the noise in the vicinity of Virgo

Need for emphasis on smart infrastructure for gravitational wave observatories

• Smart infrastructure design

• Newtonian noise modeling of infrastructure noise

• HVAC modification

Newtonian Noise Cancellation

Laboratoire des Matériaux Avancés LMA at Lyon produced the coatings used on the main mirrors of

the two working gravitational wave detectors: Advanced LIGO and Virgo. These coatings feature low

losses, low absorption, and low scattering properties

Features

- Flatness < 0.5 nm rms over central 160 mm of mirrors by using ion

beam polishing (robotic silica deposition was investigated)

- Ti:Ta2O5 and SiO2 stacks with optical absorption about 0.3 ppm

Expand LMA capabilities for next generation

LMA is the only coating group known to be capable of scaling up

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AdV+ upgrade and extreme mirror technology

LMA

© 2016 Innoseis B.V. - Confidential

AdV+ to be carried out in parallel with LIGO’s A+ upgrade

2019 2020 2021 2022 2023 2024 2025 2026

Observing Run O3 (> 60 Mpc)

Design, infrastructure preparation for AdV+

Install signal recycling (AdV) and frequency dependent squeezing (AdV+)

Observing Run O4 (> 120 Mpc)

Install AdV+ large mirror upgrades

?

AdV+ commissioning

Observing Runs

A+ fabrication

Install A+ upgrades

A+ integration into chambers

A+ commissioning

Completion AdV+ and A+

LIGO A+ Upgrade plan (see LIGO-G1702134)

Virgo AdV+ Proposed upgrade plan

Five year plan for observational runs, commissioning and upgrades

Note: duration of O4 has not been decided at this moment

AdV+ is part of a strategy to go from 2nd generation to Einstein Telescope45

© 2016 Innoseis B.V. - Confidential

Virgo’s coating R&D secures LMA’s relevance in future GW science

2019 2020 2021 2022 2023 2024 2025 2026

Observing Run O3 (> 60 Mpc)

Design, infrastructure preparation for AdV+

Install signal recycling (AdV) and frequency dependent squeezing (AdV+)

Observing Run O4 (> 120 Mpc)

Install AdV+ large mirror upgrades

?

AdV+ commissioning

Observing Runs

A+ fabrication

Install A+ upgrades

A+ integration into chambers

A+ commissioning

Completion AdV+ and A+

LIGO A+ Upgrade plan (see LIGO-G1702134)

Virgo AdV+ Proposed upgrade plan

Five year plan for observational runs, commissioning and upgrades

Note: duration of O4 has not been decided at this moment

Mirror productionUniformityon selectedmaterials

Post depositioncorrective coatingsand opticalcontrol

Material selection

GCmod.

Substrates purchasingand polishing

Metrology and handling upgrades

This cannot be achieved with existing facilities and requires a new generation of GW observatories

We want to collect high statistics (e.g. millions of BBH events), high SNR, distributed over a large z-range (z < 20)

This allows sorting data versus redshift, mass distributions, etc. Early warning, IMBH, early Universe, CW, …

3G: observing all mergers in the Universe

z = 0.45 (GW170729)

ET and CERealizing the next gravitational wave observatories is a coordinated effort to create a worldwide 3G

network

Einstein Telecope

Cosmic ExplorerET in Sardinia?48

49

Einstein Telescope has excellent sensitivityEinstein Telescope and Cosmic Explorer can observe the entire universe

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Studies of quality at potential sites in Sardinia and B-G-NLThe geology of the B-G-NL Limburg border area: hard rock with on top a layer of soft absorbing and

damping soil. In addition the region is free of disturbing (man-made) seismic activities

Antea borehole Deltares research Nikhef simulations

©2016 Innoseis B.V. - Confidential

Geologists are actively involved in underground studiesWe obtained soil samples up to a depth of 140 m. Picture: Geert-Jan Vis (TNO), Jan Lutgert (EBN),

Alessandro Bertolini (Nikhef). Research on samples at CITG in TU-Delft

Plans for detailed geological studies of B-G-NL site

are under development in Belgium

Development of a local 3G Excellence CenterRealization of a realistic test facility is under discussion. This will allow de-risking of key technologies

such as large scale cryogenic test masses, sensor development, new laser technology, controls, …

Also industry will be involved

Opportunity for training on GW instrumentation

Joint B-G-NL Limburg activity

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Einstein Telescope has excellent sensitivity for high massEinstein Telescope and Cosmic Explorer can observe the entire universe

Einstein TelescopeEinstein Telescope can observe BBH mergers to a redshift more than 20. This allows a new approach

to cosmography. Study primordial black holes, BH from population III stars (first metal producers), etc.

Einstein TelescopeEinstein Telescope can observe BBH mergers to a redshift more than 20. This allows a new approach

to cosmography. Study primordial black holes, BH from population III stars (first metal producers), etc.

Dark energy: what is ripping the universe apart?Einstein Telescope will use CBC events as standard “sirens”. This allows a new type of cosmography.

Moreover the equation of state parameter for Dark Energy can be measured

Detailed studies of gravity, near black holes. Early warning to EM follow-up community. Precision

tests of detailed aspects of CBC. Cross correlation of the largest data sets. Access to early Universe

3G science

Signals from early universe?

Gravitational wave research

• LIGO and Virgo operational

• KAGRA to join next year

• LIGO-India under construction (2025)

• ESA selects LISA, NASA rejoins

• Pulsar Timing Arrays, such as EPTA and SKA

• Cosmic Microwave Background radiation

Einstein Telescope and Cosmic Explorer

• CDR ET financed by EU in FP7, CE by NSF

• APPEC gives GW a prominent place in the new

Roadmap and especially the realization of ET

Next steps for 3G

• Organize the community and prepare a credible plan

for EU funding agencies

• ESFRI Roadmap (2020)

• Support 3G: http://www.et-gw.eu/index.php/letter-of-intent

Bright future for gravitational wave research

LIGO and Virgo are operational. KAGRA in Japan next year, LIGO-India is now under construction.

ESA launches LISA in 2034. Einstein Telescope and CE CDRs financed, strong support by APPEC